This example demonstrate how to use script automatic generate RMAN incremental backup script to sync databases. Besides it, there is a trick that address the issue it doesn’t work in sometimes.

Reference: "RMAN incremental backups can be used to synchronize a physical standby database with the primary database. Using the RMAN BACKUP INCREMENTAL FROM SCN
command, you can create a backup on the primary database that starts at
the standby database’s current SCN, which can then be used to roll the
standby database forward in time. " — Oracle manual